In many developing countries the population does not have access to modern sewage systems for taking care of faeces. Instead, usually one simply digs a hole in the ground wherein people relieve themselves. Eventually the hole is covered and the faeces is left to undergo a natural breakdown.
However, this usage inevitably causes certain sanitary problems that might be the cause of diseases.
In many of these countries also the agriculture is not particularly developed. For example fertilizers being expensive are rarely used, and the availability of natural manure is not always good.
With proper handling, human faeces could be use as fertilizer and would thereby contribute positively to agriculture.
In EP 1 156 870 (Ahlström) there is disclosed a device and method for the treatment of contaminated media. It is based on a very efficient oxygenation by a rotary impeller device that creates a very vigorous suction and mixing of air into the contaminated media.